Resonantly enhanced filamentation in gases

TL;DR

This paper reports the experimental observation of low-loss, resonantly enhanced filamentation in Krypton gas in the ultraviolet, supported by quantum calculations, revealing higher-order Kerr effects as key to intensity stabilization and extended filament length.

Contribution

It demonstrates resonantly enhanced filamentation in gases, highlighting the role of higher-order Kerr effects over ionization, and extends filament length due to decreased optical losses.

Findings

Resonant filamentation in Krypton observed experimentally.

Higher-order Kerr effects stabilize filament intensity.

Filament length significantly increased at resonance.

Abstract

In this Letter, a low-loss Kerr-driven optical filament in Krypton gas is experimentally reported in the ultraviolet. The experimental findings are supported by ab initio quantum calculations describing the atomic optical response. Higher-order Kerr effect induced by three-photon resonant transitions is identified as the underlying physical mechanism responsible for the intensity stabilization during the filamentation process, while ionization plays only a minor role. This result goes beyond the commonly-admitted paradigm of filamentation, in which ionization is a necessary condition of the filament intensity clamping. At resonance, it is also experimentally demonstrated that the filament length is greatly extended because of a strong decrease of the optical losses.